Bending press



O. OECKL BENDING PRESS Dec. 20, 1960 2 Sheets-Sheet 1 Filed April 10, 1957 N ENTOR Dec. 20, 1960 OECKL 2,965,148

BENDING PRESS Filed April 10, 195'? 2 Sheets-Sheet 2 United States Patent BENDING PRESS Otto Oeckl, Kassel-Wilhelmshoehe, Germany (Wiesengrund 13, Munchen-Pasing, Germany) This invention relates to a press for bending sheet material, such as sheet metal, and has particular relation to a sheet bending press in which the punch and dye members have slidable parts to provide alternate reversing operation.

In the conventional method of sheet bending or forming, a press is provided with a suitably shaped rail which is depressed under pressure from above and acts on a punch to press the metal sheet strip into a groove-shaped tool or dye located therebeneath. Such operation causes the two legs of the sheet to swing upwardly. Often, however, sections are required to be made with legs extending outwardly at both sides, that is to say: the sheet must be bent first to one side and then to the other, and so on. As a result, the workpiece must be laid down, pressed, and then turned around lengthwise before the next bend can be applied. This procedure is time consuming and expensive.

It is an object of the invention herein to provide a bending press in which the workpiece can be bent upwardly or downwardly, as desired, in uninterrupted sequence, without the necessity of changing the bending tools. The legs of the sheet may be bent out in all directions, upwardly or downwardly.

Another object of the invention is to provide a bending press of the character described, in which each of the two bending tools or parts, that is to say; upper and the lower tool may be transformed selectively into either a punch or a die, as desired, by suitable means, for example a sliding wedge. This may be done when the machine is at rest or when it is in operation. Such interchangeability enables the upward or downward bending of the sheet material alternately as desired, without moving or turning the sheet material.

Another object of the invention is to provide a bending press which can produce obtuse angles in the sheet material. For this purpose, the purchase of the movable tool is reduced by means of a purchase controlling reversible motor, the action of which is controlled by special contacts or switches. I

A further object of the invention is to provide a bending press in which the entire bending process may be accomplished semi-automatically. To accomplish this semiautomatic operation, there is provided in addition to the rail serving as the rear stop, a front stop rigidly connected to the rear stop, with both stops controlled by a cam disc, the configuration of which depends on the number of bends to be applied to the material to be worked. i

A still further object of the invention is to provide a bending press in which transparent instruction plates are provided at the eye level of the operator, these instruction plates being illuminated by light flashing there-behind to instruct the operator in the use of the machine. The various light sources may be controlled by the various cam portions of the cam disk.

Additional objects and advantages of the invention will become apparent during the course of the following Patented Dec. 20, 1960 specification when taken in connection with the accompanying drawings, in which:

Fig. 1 is an elevational view of a press made in accordance with the invention, with certain portions thereof broken away or shown in section to reveal the construction thereof, and those portions of the press which are conventional being eliminated for clarity of illustration, the tools being shown in a position to bend the sheet metal upwardly;

Fig. 2 is an enlarged section of the tool section of the press corresponding to that shown in Fig. 1, except that the tools are shown in a position to bend the sheet material downwardly;

Fig. 3 is a partial elevation showing the drive mechanism for the cam which controls the stop rail assembly; and

Figs. 4 and 5 are schematic elevational views shown partly in section, illustrating the drive arrangement forthe toolinsets, Fig. 4 showing the inset in retracted position-and Fig. 5 showing the inset in advanced posif tion.

Referring to Fig. l, the bending press of the invention comprises a frame 16, to which an upstanding tool or support 1 is secured, as by bolts 13. The upper tool or support 10 is fixed to and carried by a movable upper portion of the machine (not shown), which operates in the usual manner to descend for the punching operation. The tools 1 and 10 have angularly-disposed heads 1a and 10a, the working faces of which are provided with respective longitudinally-extending grooves or recesses 14 and 15, as shown in the drawings. A pair of inset members 3 and 4 are mounted for sliding movement longitudinally in the respective grooves 14 and 15.

The inset members 3 and 4 have forward perpendicular edges, and each can be slid in its respective groove to form an edge 3b or a groove 3a depending upon its position. This can be most clearly seen in Fig. 2, in which the inset 4 is spaced rearwardly of the front edge of tool head 10a to provide the forward angular groove or die 3a. At the same time, the inset 3 is located forwardly in its slot, so that its front face is flush with or located slightly forwardly of the front end of tool head 1a, thereby forming the working edge or angular punch 3b. A change of position of the inset members 3 and 4 may be effected by sliding wedges 2, or other known means. For this purpose, the inset members 3 and 4 may have inclined rear ends to conform to the inclined edges of the wedges 2.

By retracting the member 3 on the lower tool 1 and advancing the member 4 on the upper tool 10, the upper tool becomes an edge or punch and the lower tool a groove or die, as shown in Fig. 1. In this instance, the sheet will be bent upwardly, while in the position of Fig. 2 the sheet is bent downwardly. The slidable reposition ing of the inset members 3 and 4 may be accomplished automatically by operation of the cam assembly and slide arrangement shown in Figs. 4 and 5, the cam of which may be designed in correspondence to the desired bending sequence.

The arrangement shown in Figs. 4 and 5 is intended to actuate the inset member 3, it being understood that a similar arrangement is used for actuation of the inset member 4. The control of inset member 3 is effected by a rotating disc 18 having cam surfaces 19 and 19a. These cam surfaces act on the pin or plunger 21 of a hydraulic valve 20. The valve 20 is arranged to permit the passage of oil or other hydraulic medium therethrough in opposite directions depending upon whether the plunger 21 is depressed or retracted.

The valve 20 is connected to a pressure chamber 22 in which a piston 23 is contained. The piston rod 24 is connected to the wedge 2 for actuating the latter in a' 3 manner to be presently described. As shown in Figs. 4 and 5, both the wedge 2 and inset member 3 are toothed on their facing sides, providing a successlon of cooperating corresponding inclined surfaces 20 and 3e.

Fig. 4 shows the inset member 3 in its retracted position, corresponding to the position shown in Fig. 1. R- tation of disc 18 brings the cam surface 19 into engagement with the valve plunger 21, thereby depressing plunger 2.1 and causing oil or other hydraulic medium to flow into the pressure chamber 22 behind the piston 23. The piston 23 is thus driven to the left as viewed in Fig. 4, moving to its operative position of Fig. in which it drives the wedge 2 to the left and brings the upper portions of the inclined surfaces 20 of the wedge teeth into registry with the upper portions of the inclined surfaces 30 of the inset member teeth. The inset member 3 is therefore moved transversely forwardly to its advanced position shown in Figs. 2 and 5.

The inset members 3 and 4 may be guided by bolts 5a mounted for sliding movement in slot 5, as shown in Figs. 1 and 2. Alternately, a plurality of guide slots 27 and cooperating pins may be employed, as shown in Figs. 4 and 5 to insure that movement of the inset members is limited to a forward and rearward direction.

As the disc 18 continues to rotate, the cam surface 19a comes into engagement with the plunger 21, allowing the plunger to retract, and actuatingvalve 20 to feed the hydraulic medium to the pressure chamber 22 in front of the piston 23, thereby moving piston 23 to the right. The wedge 2 is thereby moved to the right from its position of Fig. 5 to its original position of Fig. 4. A tension spring 26 connected to the inset 3 and wedge 2 thereupon moves the inset 3 rearwardly back into registering engagement with the wedge 2, that is to say back to its position of Fig. 4.

Location of the sheet S during the bending operation is determined by indexing means in the nature of a stop member. It is known to provide a stop rail 9in bending machines. According to the invention herein, a second stop rail 6 is provided on the side of the machine at which the operator is stationed, that is: the left-hand side of the machine as viewed in Fig. 1. Stop rails 6 and 9 form positioning guides for sheet metal. The sheet is placed between the bending tools and pushed backwardly until an edge strikes a respective stop 6 or 9 depending on which side of the machine it is inserted. This locates the sheet in correct position for bending. In Fig. 1 a sheet S (shown dotted) is shown between stop rails 6 and 9 before the bending process takes place. After the sheet is bent, it will assume the shape indicated by the sheet S (shown in solid lines). The stop rails may work singly or jointly depending on whether the sheet is guided on both sides of the press or on one side only. Both rails 6 and 9 are mounted on supports 6a and 9a respectively. The supports 6a and 9a are adjustably mounted on the horizontal shaft 7 which is axially movable. By this arrangement, any position of movement of rail 9 is translated to a corresponding movement of rail 6' inthe same directional sense. The shaft 7, carrying the stop rails 6 and 9, may be mounted for sliding movement on ball bearings. Such sliding or axial movement of shaft 7 is guided horizontally by swing arm 8, and is controlled by cam disc 11. A tension spring 17, or other suitable biasing means may be used to maintain the rail 9 in contact with the cam surface of cam disc 11 The configuration of cam disc 11 is determined by the number of bends to be applied to the sheets 8. The cam disc 11 is rotatably and interchangeably mounted on the machine frame, so that it may be replaced by a cam disc of different shape in subsequent bending operations. During one complete bending cycle, which correangle during that'portion of the bending cycle, in which the upper tool 10 is raised, i.e. out of engagement with the sheet S.

Fig. 3 shows a preferred form of drive means for the cam 11. This drive means comprises a reversible electric motor upon the shaft of which a worm 11b is mounted. The worm 11b meshes with a worm gear 11a secured in driving relationship to the cam 11. The operation of the electric motor 110 may be controlled by the movement of the press portion carrying the upper tool 10 the usual switch means being employed for this purpose. The cam' disc 11 may therefore be controlled in synchronization with or independently of the stop mechanism.

The parallel guiding of the stop rails 6 and 9 is effected by the swing arm 8 or by a pair of such swing arms which may be pivoted on top and at the bottom of the frame structure, and are swingable on an axis parallel to the stop rails 6 and 9.

The vertical lift and depression of the upper movable tool or support 10 may be controlled by a reversible motor, which is usually controlled by manually-actuated switches according to conventional procedures. In accordance with the present invention, this switching may be controlled automatically by an additional cam disc, the operation of which will be apparent to those skilled in the art, and which is therefore not shown.

Instructions forthe operator are given at eye level by optical signals whichare illuminated at the proper time by a similar switches arrangement controlled by a cam disc. These instructions may be printed on transparent panes set within the machine frame and back-lighted by electric bulbs controlled automatically by the afore-rnentioned switch and cam arrangement. At the proper time an appropriate instruction transparency can thus be illuminated, instructing the operator, for example to use front stop, use rear stop, etc. Thus, the operator may be informed of his necessary function at each bending step, and the operation of the press is made as automatic as is possible.

The operating edges of the inserts 3 and 4 of the tool heads 1a and 10a may be made of hard metal or may contain hard metal reinforcements 12 to insure against wear in operation.

The bending press can also produce obtuse angles in the sheet S. For this purpose, the purchase of the movable tool is reduced by means of a purchaser-controlling reversible motor, the action of which is controlled by special switch contacts.

While a preferred embodiment of this invention has been shown and described for purposes of illustration, it is obvious that-numerous additions, structural changes, and omissions may be made in this embodiment without departing from the spirit and scope of the invention.

What is claimed is:

1. A-bending press for bending sheet material comprising upper and lower bending tools having movable working surfaces positioned to form selectively a punch and a die, means for selectively transforming the bending tools selectively and alternately to punch and die for bending the sheet material upwardly and downwardly during a continuously running working operation of the press, a front stop rail and a rear stop rail for indexing positioning of the sheet to be bent, the stop rails being rigidly connected to each other, for simultaneous movement, the connection of said rails being adjustable.

2. A bending press according to claim 1 in which a cam disc controls the movement of said stop rails, the cam disc having a cam surface shaped to correspond to the number of bends to be made in the sheet material.

3. A bending press according to claim 2, in which the camdisc is driven in synchronization with the mechanism for actuating the bending tools.

4.- A bending press according to claim 1, in which the stop-rails are guided-for parallel movement by at least one swing arm, said swing arm being pivoted on the press frame on a pivotal aXis parallel to said stop rails.

5. A bending press according to claim 1, in which the upper tool is movable and the lower tool is fixed, and in which a cam disc controls the movement of said stop rails, the cam disc having a cam surface shaped to correspond to the number of bends to be made in the sheet material, the cam disc being driven in synchronization With the movement of the upper tool.

6. A bending press according to claim 5, in which the operators station of the press is provided with eye-level optical signal indicators to direct the operator in the necessary operations.

7. A bending press for bending sheet material, comprising upper and lower bending tools having respectively upper and lower operative ends opposite each 15 other, said upper and lower tools having longitudinal grooves coextending respectively with said operative ends and located adjacent thereto, upper and lower inset members having respectively substantially lesser widths than said grooves and being slidably mounted therein, said inset members being movable into an extended position in which said inset members are at the forward end of said respective grooves adjacent to the operative end of the tool, and into a retracted position in which said inset members are slid to the rear end of their respective grooves away from the operative end of the tool, and actuating means for moving said inset members selectively to their respective extended and retracted positions, said actuating means including a wedge movably mounted in each of the respective grooves in abutment with the rear ends of said inset members.

References Cited in the file of this patent UNITED STATES PATENTS 348,423 Shackleton Aug. 31, 1886 1,084,429 Harner Jan. 13, 1914 1,687,776 Macomber Oct. 16, 1928 2,426,446 Funk Aug. 26, 1947 2,808,095 Loughlin et al. Oct. 1, 1957 FOREIGN PATENTS 430,271 Italy Feb. 12, 1948 

